Macromolecular organization of ATP synthase and complex I in whole mitochondria
Proceedings of the National Academy of Sciences
National Academy of Sciences
Freely available online through the PNAS open access option.
We used electron cryotomography to study the molecular arrangement of large respiratory chain complexes in mitochondria from bovine heart, potato, and three types of fungi. Long rows of ATP synthase dimers were observed in intact mitochondria and cristae membrane fragments of all species that were examined. The dimer rows were found exclusively on tightly curved cristae edges. The distance between dimers along the rows varied, but within the dimer the distance between F1 heads was constant. The angle between monomers in the dimer was 70° or above. Complex I appeared as L-shaped densities in tomograms of reconstituted proteoliposomes. Similar densities were observed in flat membrane regions of mitochondrial membranes from all species except Saccharomyces cerevisiae and identified as complex I by quantum-dot labeling. The arrangement of respiratory chain proton pumps on flat cristae membranes and ATP synthase dimer rows along cristae edges was conserved in all species investigated. We propose that the supramolecular organization of respiratory chain complexes as proton sources and ATP synthase rows as proton sinks in the mitochondrial cristae ensures optimal conditions for efficient ATP synthesis
This work was supported by the Max Planck Society (W.K., K.D., M.S., B.D., and A.R.), the Deutsche Forschungsgemeinschaft (A.W., H.O., and V.Z.), and the Deutsche Forschungsgemeinschaft–funded Cluster of Excellence Frankfurt “Macromolecular Complexes” (W.K., H.O., and J.K.).
This is the final version of the article. Available from National Academy of Sciences via the DOI in this record.
Vol. 108, pp. 14121 - 14126